BMW vehicles go greener on fewer cylinders, less gasoline

Jason H. Harper, Bloomberg News |
April 4, 2013

Or more accurately, it's working on a bunch of them, pushing to create an efficient fleet of cars that are still a blast to drive. I recently tested three BMW vehicles, each representing a different prong of the Munich-based company's green efforts.

First, I got a chance to drive a test car with an odd and surprising three-cylinder engine. This efficient engine will eventually be put into the company's future hybrid sports car, the i8.

Next came a diesel-powered version of the 3 Series, the company's perennially-heralded sedan.

Lastly, I spent a week in the X1, the company's smallest- ever SUV, offered with a four-cylinder engine.

BMW, which has long touted itself as the "Ultimate Driving Machine," a few years ago came out with the tag line "Efficient Dynamics. Less Emissions. More Driving Pleasure." At the time I thought it was just green speak.

However unlike some competitors, the company has rolled out a steady stream of models with alternative powertrains. These days you can buy a 5 Series with a 2.0-liter, four-cylinder engine; an X5 SUV powered by diesel and a hybrid 7 Series executive sedan. The company has also performed limited consumer testing with all-electric 1 Series coupes. (Testers were dubbed "electronauts.")

Three Cylinders

Just before last week's New York International Auto Show, I went to BMW's U.S. headquarters in Woodcliff Lake, New Jersey to meet several engineers from Germany who are developing a new, 1.5-liter, turbo-charged, three-cylinder engine.

Such a small engine would seem to be anathema for a company known for inline six-cylinders, which have a distinct sound and feel. Yet BMW's engineers pointed out that mechanically and sonically, the three-cylinder is more similar to a six-cylinder than a four -- basically, it's a six-cylinder lopped in half.

They said the smaller engine will produce between five and 15 percent less C02 emissions than the four-cylinder.

It will first appear in BMW's i8 plug-in hybrid sports coupe, slated for production next year.The i8 looks suitably mean and fast in a science fiction kind of way, and will be powered by both the three-cylinder engine and an electric motor.

Mini Cooper

With no i8 test mule available, I made do with a hand-built three-cylinder installed in a European-spec 1 Series hatchback. (BMW has no plans to release a three-banger 1 Series, they say. I wouldn't be surprised to find the small engine in a Mini Cooper in the near future, though.)

From a hard start, the turbo on the engine took a moment to spool up, but it was punchy and confident as it reached peak power. The engine also sounded throatier and rawer than a four- cylinder, almost like a rally car from the 1980s.

The engineers said it was tuned to 174 horsepower and 199 pound-feet of torque as tested, but that it would be more powerful in the i8.

Also on hand was a 328d, a 3 Series model powered by a 2.0- liter turbo-charged four-cylinder diesel engine. This engine is familiar to Europeans, and the 328d will make its U.S. debut in the fall. (The six-cylinder 335d was sold here for a short time.)

The engine runs on ultra-low-sulfur diesel, and should get about 32 miles per gallon in the city and as much as 45 mpg on the highway. Horsepower is 180, with 280 pound-feet of torque. It will also be offered as an all-wheel-drive and as a wagon. Expect it to be priced above the base 328i.

Fuel Savings

Motoring around some New Jersey hills, I was pleased. The diesel 328 isn't fast (60 mph arrives in some seven seconds), but it is awash in low-end grunt. Freeway commutes will surely see fewer fuel stops.

To see how efficient dynamics translate to the real world, I turned to a production vehicle, the 2013 model-year X1 xDrive28i. (Base of $32,500; $45,595 as tested.) The X1 is built on the chassis of the small 1 Series coupe, and it's a bit of a griffin: Taller than a sedan, fatter than a wagon, not quite a SUV.

I like the idea of a smaller, lighter SUV. The all-wheel- drive X1 weighs around 3,700 pounds and gets 22 mpg city, 33 highway. Compare that to the X3's 4,100 pounds and 21, 28 mpg, and you've got a good case for smaller vehicles.

The available four-cylinder, with 240 hp, is rarely found wanting.

Body Roll

Unfortunately, the X1 excels at nothing. It has a similar ground clearance to a sedan; doesn't handle nearly as well as the regular 128i coupe (too much body roll); and is homely. An awkward rear storage cover impedes you from stacking up stuff in the back.

The X1 is a good reminder for both BMW and potential buyers that efficiency alone doesn't make a great car. It may be greener, but it isn't a blast to drive.